Most strains of this bacteria are harmless, but some can cause serious symptoms. Learn about symptoms and treatment of this common foodborne illness.
Update Date: 13.03.2026
Escherichia coli, also called E. coli, bacteria live in the intestines of people and animals. Most types of E. coli cause no harm or mild illness. But a few strains, such as E. coli 0157:H7, can cause bad stomach cramps, bloody loose stools and vomiting, called diarrheal infection.
People can get E. coli diarrheal infection from tainted water or food, mainly raw vegetables and ground beef that isn't cooked through. Adults with no other health concerns most often get better within a week. Young children and older adults have more risk of getting a life-threatening form of kidney failure.
Symptoms of E. coli diarrheal infection most often begin 3 to 4 days after contact with the bacteria. But symptoms can start as soon as one day after contact. Or they can begin more than a week later. Symptoms of E. coli diarrheal infection may include:
Contact a healthcare professional if you have loose stools for more than two days or your stools are bloody.
Only a few strains of E. coli cause loose stools. These strains make a strong toxin that harms the lining of the small intestine. You get this type of E. coli infection by eating or drinking something with these strains of the bacteria. You also can get E. coli from contact with a person or an animal with the bacteria.
One way to get an E. coli infection is by eating tainted food, such as:
Human and animal stool may taint ground and surface water. This includes streams, rivers, lakes and water used to grow crops. Although public water systems use chlorine, ultraviolet light or ozone to kill E. coli, some E. coli outbreaks have been linked to tainted city water supplies. Some people have been infected with E. coli after swimming in pools or lakes tainted with stool.
E. coli bacteria can go from person to person, mainly when infected adults and children don't wash their hands well. Family members of young children with E. coli infection are likely to get it themselves. Outbreaks also have happened among children who visit petting zoos or animal barns at county fairs.
E. coli can affect anyone who has contact with the bacteria. But some people are more likely to get ill than others are. Risk factors include:
For some people with certain strains of E. coli, a complication of E. coli infection is a life-threatening form of kidney failure called hemolytic uremic syndrome. Young children and older adults are at higher risk.
To lower your chance of having contact with E. coli, do the following:
To diagnose E. coli infection, a healthcare professional sends a sample of your stool to a lab to test for the E. coli bacteria.
Most people with E. coli diarrheal infection get better on their own. Rest and drink fluids to keep the body from losing too much fluid, called dehydration. Don't take antidiarrheal medicine. It slows your digestive system and keeps your body from getting rid of the toxins.
Some people with serious E. coli diarrheal infection or those at high risk of complications may take an antibiotic to help clear the infection. But for people who have a strain that can cause a life-threatening form of kidney failure called hemolytic uremic syndrome, taking antibiotics can raise the risk.
If your E. coli infection causes hemolytic uremic syndrome, you need treatment in a hospital. Treatment may include getting fluids through a vein, blood from donors and kidney dialysis, a procedure to clear waste from the kidneys.
Follow these tips to prevent fluid loss, called dehydration, and ease symptoms while you recover:
When you start feeling better, you can return to your usual diet.
Most people don't see a healthcare professional for E. coli infections. If your symptoms are bad, you may want to visit your main healthcare professional or go to an emergency room.
Here's some information to help you get ready for your appointment.
Make a list of:
For an E. coli infection, some questions to ask include:
Your healthcare professional may ask:
If you or your child has an E. coli infection, don't use an antidiarrheal medicine. Having loose stools is one way the body gets rid of toxins. Taking an antidiarrheal medicine slows that process. As you're able, take small sips of fluid to replace fluid lost while you have diarrhea.
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